Golden orbs dropping in on a wind and a prayer

Some of Sydney's favourite arachnids are again calling Olympic Park their home, thanks to fickle winds and pure chance.The canopy-like webs of the golden orb spiders are once again decorating the park's mangrove-lined boardwalks.

It has been three years since the species last called the park their home, and their return was mostly due to luck, said Mike Gray, an arachnologist with the Australian Museum.

Each spring the young put out a long line of silk that enabled them to be yanked up into the air and carried off on the breeze, he said. "They'll live wherever they fall. If you get favourable wind currents you will see them all dumped in the one spot, and that will become the new golden orb hot-spot."

The species can move many kilometres in a single wind-fuelled adventure, and one golden orb species has colonised a large part of Australia's interior.

The golden orbs are not dangerous to humans, although the same cannot be said for prey caught in their webs. They produce the strongest and largest web of any Australian spider.

Small birds and bats were often entrapped, and even they could end up as lunch, Dr Gray said.